/*******************************************************************************
 *     ___                  _   ____  ____
 *    / _ \ _   _  ___  ___| |_|  _ \| __ )
 *   | | | | | | |/ _ \/ __| __| | | |  _ \
 *   | |_| | |_| |  __/\__ \ |_| |_| | |_) |
 *    \__\_\\__,_|\___||___/\__|____/|____/
 *
 *  Copyright (c) 2014-2019 Appsicle
 *  Copyright (c) 2019-2024 QuestDB
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 ******************************************************************************/

package io.questdb.griffin.engine.functions.date;

import io.questdb.cairo.CairoConfiguration;
import io.questdb.cairo.ColumnType;
import io.questdb.cairo.MicrosTimestampDriver;
import io.questdb.cairo.sql.Function;
import io.questdb.cairo.sql.Record;
import io.questdb.cairo.sql.SymbolTableSource;
import io.questdb.griffin.FunctionFactory;
import io.questdb.griffin.PlanSink;
import io.questdb.griffin.SqlException;
import io.questdb.griffin.SqlExecutionContext;
import io.questdb.griffin.engine.functions.TimestampFunction;
import io.questdb.std.IntList;
import io.questdb.std.Misc;
import io.questdb.std.Numbers;
import io.questdb.std.ObjList;

public class TimestampSequenceFunctionFactory implements FunctionFactory {
    private static final String NAME = "timestamp_sequence";
    private static final String SIGNATURE = NAME + "(NL)";

    @Override
    public String getSignature() {
        return SIGNATURE;
    }

    @Override
    public Function newInstance(
            int position,
            ObjList<Function> args,
            IntList argPositions,
            CairoConfiguration configuration,
            SqlExecutionContext sqlExecutionContext
    ) {
        int timestampType = ColumnType.TIMESTAMP_MICRO;
        Function arg = args.getQuick(0);
        if (arg.isConstant()) {
            final long start = MicrosTimestampDriver.INSTANCE.from(arg.getTimestamp(null), arg.getType());
            if (start == Numbers.LONG_NULL) {
                return MicrosTimestampDriver.INSTANCE.getTimestampConstantNull();
            }
            return new TimestampSequenceFunctionFactory.TimestampSequenceFunction(NAME, start, args.getQuick(1), timestampType);
        } else {
            return new TimestampSequenceFunctionFactory.TimestampSequenceVariableFunction(NAME, args.getQuick(0), args.getQuick(1), timestampType);
        }
    }

    public static class TimestampSequenceFunction extends TimestampFunction {
        private final Function longIncrement;
        private final String name;
        private final long start;
        private long next;

        public TimestampSequenceFunction(String name, long start, Function longIncrement, int timestampType) {
            super(timestampType);
            this.start = start;
            this.next = start;
            this.longIncrement = longIncrement;
            this.name = name;
        }

        @Override
        public long getTimestamp(Record rec) {
            final long result = next;
            next += longIncrement.getLong(rec);
            return result;
        }

        @Override
        public void init(SymbolTableSource symbolTableSource, SqlExecutionContext executionContext) throws SqlException {
            longIncrement.init(symbolTableSource, executionContext);
            next = start;
        }

        @Override
        public boolean isNonDeterministic() {
            return true;
        }

        @Override
        public boolean shouldMemoize() {
            return true;
        }

        @Override
        public boolean supportsRandomAccess() {
            return false;
        }

        @Override
        public void toPlan(PlanSink sink) {
            sink.val(name).val("(").val(start).val(',').val(longIncrement).val(')');
        }

        @Override
        public void toTop() {
            next = start;
        }
    }

    public static final class TimestampSequenceVariableFunction extends TimestampFunction {
        private final Function longIncrement;
        private final String name;
        private final Function start;
        private long next;

        public TimestampSequenceVariableFunction(String name, Function start, Function longIncrement, int timestampType) {
            super(timestampType);
            this.start = start;
            this.next = 0;
            this.longIncrement = longIncrement;
            this.name = name;
        }

        @Override
        public void close() {
            Misc.free(start);
            Misc.free(longIncrement);
        }

        @Override
        public long getTimestamp(Record rec) {
            final long result = next;
            next += longIncrement.getLong(rec);
            return result + start.getLong(rec);
        }

        @Override
        public void init(SymbolTableSource symbolTableSource, SqlExecutionContext executionContext) throws SqlException {
            start.init(symbolTableSource, executionContext);
            longIncrement.init(symbolTableSource, executionContext);
            next = 0;
        }

        @Override
        public boolean isNonDeterministic() {
            return true;
        }

        @Override
        public boolean supportsRandomAccess() {
            return false;
        }

        @Override
        public void toPlan(PlanSink sink) {
            sink.val(name).val("(").val(start).val(',').val(longIncrement).val(')');
        }

        @Override
        public void toTop() {
            next = 0;
        }
    }
}
